Probiotic Supplementation in Chronic Kidney Disease: A Double-blind, Randomized, Placebo-controlled Trial

Gut microbiome dynamics of patients on dialysis: implications for complications and treatment

The gut microbiome plays a significant role in dialysis. As disease progresses, the choice of dialysis method and dietary habits change, and the diversity and richness of the gut microbiome in patients on dialysis change as well. The uremic toxins produced exacerbate inflammatory responses and oxidative stress, leading to markedly different incidence rates of complications such as cardiovascular disease and dialysis-associated peritonitis among patients on dialysis. The intake of probiotics, prebiotics, synbiotics, and natural medicines during daily life can regulate the gut microbiome, reduce the production of uremic toxins in patients on dialysis. This review found that the occurrence of complications in dialysis patients is related to changes in the gut microbiome and the accumulation of uremic toxins. The use of probiotics, prebiotics, synbiotics, and natural medicines can improve these conditions and reduce the incidence of dialysis-related complications.

Effects of Probiotic-Enriched Minas Cheese (Lactobacillus acidophilus La-05) on Cardiovascular Parameters in 5/6 Nephrectomized Rats

Dairy foods have become an interest in chronic kidney disease (CKD) due to their nutritional profile, which makes them a good substrate for probiotics incorporation. This study evaluated the effect of probiotic-enriched Minas cheese with Lactobacillus acidophilus La-05 in an experimental rat model for CKD on cardiac, inflammatory, and oxidative stress parameters. Male Wistar rats were divided into 4 groups (n = 7/group): 5/6 nephrectomy + conventional Minas cheese (NxC); 5/6 nephrectomy + probiotic Minas cheese (NxPC); Sham + conventional Minas cheese (ShamC); Sham + probiotic Minas cheese (ShamPC). Offering 20 g/day of Minas cheese with Lact. acidophilus La-05 (108-109 log CFU/g) for 6 weeks. The cardiomyocyte diameter was determined. Superoxide dismutase (SOD) activity in plasma, heart, kidney, and colon tissue was performed. At the end of supplementation, no significant changes in lipid profile and renal parameters were found. The NxPC group showed a decrease in cardiomyocyte diameter compared to the NxC group (16.99 ± 0.85 vs. 19.05 ± 0.56 μm, p = 0.0162); also they showed reduced plasmatic SOD activity (502.8 ± 49.12 vs. 599.4 ± 94.69 U/mL, p < 0.0001). In summary, probiotic-enriched Minas cheese (Lact. acidophilus La-05) consumption suggests a promisor cardioprotective effect and was able to downregulate SOD activity in a rat model of CKD.

Native potential probiotics and postbiotics improve the gut-kidney axis by the modulation of autophagy signaling pathway

The gut-kidney axis is the bidirectional relationship between the gut microbiota and the kidney function. Chronic inflammatory responses can impair kidney function and probiotics and postbiotics agents can have positive effects on gut health and kidney function by modulating inflammation through affecting autophagy signaling pathway. The aim of the current study was to evaluate the properties of our probiotic and postbiotics to improve kidney health by focusing the autophagy signaling pathway. The probiotic and postbiotics of four Lactobacillus and two Bifidobacterium strains were selected. Dextran sulfate sodium induced colitis in mice, and probiotics and postbiotics treatments were accomplished in animal experiment. A qPCR assay was performed to assess the gene expression involved in the autophagy process in the kidney. In contrast to the dextran sulfate sodium group, both the probiotic and postbiotics cocktails exhibited the capacity to inhibit colitis-associated indicators. Of note, the postbiotics cocktails demonstrated a greater efficacy in preventing colitis-related indicators and also it could display a more pronounced effect in upregulating autophagy-related genes. Our native potential probiotics and postbiotics can be able to reduce gut inflammation and cope with kidney inflammation by triggering autophagy signaling pathway through the considerable impact on gut-organ axis. There is an encouraging concept about the anti-inflammatory effects of our probiotics and postbiotics cocktails with least side effects as a supplementary treatment not only in the gut, but also in the other organs particularly kidneys.

Nanobiotechnology Unveils the Power of Probiotics: A Comprehensive Review on the Synergistic Role of Probiotics and Advanced Nanotechnology in Enhancing Geriatric Health

The geriatric population, comprising ages 65 and above, encounters distinct health obstacles because of physiological changes and heightened vulnerability to diseases. New technologies are being investigated to tackle the intricate health requirements of this population. Recent advancements in probiotics and nanotechnology offer promising strategies to enhance geriatric health by improving nutrient absorption, modulating gut microbiota, and delivering targeted therapeutic agents. Probiotics play a crucial role in maintaining gut homeostasis, reducing inflammation, and supporting metabolic functions. However, challenges such as limited viability and efficacy in harsh gastrointestinal conditions hinder their therapeutic potential. Advanced nanotechnology can overcome these constraints by enhancing the efficacy of probiotics through nano-encapsulation, controlled delivery, and improvement of bioavailability. This review explores the synergistic potential of probiotics and advanced nanotechnology in addressing age-related health concerns. It highlights key developments in probiotic formulations, nano-based delivery systems, and their combined impact on gut health, immunity, and neuroprotection. The convergence of probiotics and nanotechnology represents a novel and transformative approach to promoting healthy aging, paving the way for innovative therapeutic interventions.

Genetically predicted inflammatory proteins mediate the association between gut microbiota and renal cell carcinoma

BACKGROUND

Studies have indicated a potential relationship between gut microbiota and renal cell carcinoma. However, the causal relationship between various types of gut microbiota and renal cell carcinoma, as well as the role of inflammatory protein as mediators, remains unclear.

METHODS

This study aimed to identify the relationship between gut microbiota, inflammatory protein, and renal cell cancer through a large-scale genome-wide association study (GWAS) utilizing pooled data. We employed Mendelian randomization (MR) to investigate the causal relationship among these variables. Inverse variance weighting (IVW) was utilized as the primary statistical method. Furthermore, we examined the mediating role of inflammatory protein in the pathway through which gut microbiota influences the development of renal cell cancer.

RESULTS

The analysis revealed 12 positive causal relationships and 15 negative causal relationships between the genetic liability of gut microbiota and renal cell cancer. Furthermore, there were three positive causal relationships and one negative causal relationship between inflammatory proteins and renal cell cancer. There were two axes of relationships in which gut microbiota promote the development of renal cell cancer. through inflammatory proteins acting as mediators.

CONCLUSIONS

Gut microbiota and inflammatory protein were causally related to renal cell cancer, and inflammatory protein were intermediary factors in the pathway between gut microbiota and renal cell cancer.

Benefits and Pitfalls of Uraemic Toxin Measurement in Peritoneal Dialysis

Chronic kidney disease is a global health burden with a rising incidence and prevalence in developed and developing nations. Once established, it results in a progressive accumulation of a myriad of uraemic toxins. Peritoneal dialysis (PD) uses the body's peritoneal membrane to remove these toxins across a semipermeable membrane to restore and maintain homeostasis. Traditionally, dialysis adequacy has been measured through clearance of urea and creatinine. However, numerous studies have shown marginal links comparing the clearance of urea and creatinine with clinical outcomes reflected in the recent changes to the ISPD guidelines on dialysis adequacy. Instead, attention has focused on protein-bound uraemic toxins (PBTs). Produced by gut bacteria, these molecules are highly protein-bound and poorly removed by either dialysis or absorptive agents. Elevated concentrations of molecules such as p-cresyl sulfate and indoxyl sulfate have been associated with abnormal cellular function and poor patient outcomes. However, widespread use of these measures to determine dialysis adequacy has been limited by the need for specialized techniques required for measurement. Altering the gut microbiome to reduce generation of PBTs through increased dietary fiber might be an alternate approach to better patient outcomes, with some initial positive reports. This report explores advantages and limitations of measuring uraemic toxins in PD, now and in the foreseeable future.

Progress in the investigation of the Firmicutes/Bacteroidetes ratio as a potential pathogenic factor in ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) that presents significant challenges in terms of treatment owing to a pronounced likelihood of recurrence and an elevated risk of cancer development, thereby imposing substantial risks on affected individuals. The gut microbiota of Firmicutes and Bacteroidetes (F/B) can affect diseases associated with IBD, which is also a risk factor for breast cancer. This review discusses the hazards associated with UC, highlights the existing disparities in UC-associated gut microbiome research, explores the concept of the F/B ratio and scrutinizes its correlation with UC. Moreover, the differences in the F/B ratios between healthy individuals and those with UC were thoroughly examined. These findings suggest that an elevated F/B ratio may promote the occurrence and progression of UC. Consequently, the F/B ratio may play a significant role in UC by influencing gut microbiota composition and inflammatory responses, suggesting that future research should focus on this ratio as a potential biomarker for disease progression and therapeutic targets in managing UC.

Efficacy of probiotic, prebiotic, and synbiotics supplements in individuals with anemia: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Anemia is a common global health problem, particularly in impoverished regions, with a high incidence rate. The condition is multifactorial, with iron deficiency being one of the most prevalent causes. Current treatment for anemia often relies on iron supplements or erythropoiesis-stimulating agents, although these therapies may show limited efficacy for some patients. Recent evidence suggests that probiotics, prebiotics, and synbiotics, as microbiome modulators, hold significant potential in the treatment of anemia. These interventions may enhance iron absorption and improve overall blood health through their impact on gut microbiota, thus providing an alternative or complementary approach to conventional treatments.

METHODS

Six databases, including the Cochrane Central Register of Controlled Trials, Embase, PubMed, Web of Science (WOS), China National Knowledge Infrastructure (CNKI), and WangFang data library, were searched up to November 20, 2024. Studies published in English and Chinese were included. We included randomized controlled trials (RCTs) evaluating the effects of probiotics, prebiotics, or synbiotics in treating anemia. The experimental groups received probiotics, prebiotics, or synbiotics, while the control groups received placebo, alternative treatments, or no treatment. The primary outcome was hemoglobin (Hb) levels. Secondary outcomes included serum iron (SI) and serum ferritin (SF). A descriptive analysis was conducted for studies where meta-analysis was not feasible. The GRADE tool was used to assess the quality of evidence, and the Cochrane guidelines were employed to evaluate the risk of bias in each study.

RESULTS

Seven studies were included comprising a total of eight RCTs, with the main types of anemia being iron deficiency anemia (IDA) and anemia of chronic kidney disease (CKD), involving 632 patients. The analysis revealed that probiotics, prebiotics, or synbiotics significantly improved Hb levels in patients with anemia (WMD = 10.760, 95% CI: 4.593 to 16.747, p = 0.001), though heterogeneity was high (I² = 96.5%). Two RCTs (n = 120 participants) reported significant increases in serum iron levels in the probiotic group (WMD = 3.835, 95% CI: 3.271 to 4.400), with moderate heterogeneity (I² = 38.7%). Two RCTs (n = 192 participants) reported no significant differences were observed between the groups in serum ferritin levels (WMD = 8.048, p = 0.115), and heterogeneity remained high (I² = 62.6%). Subgroup analyses revealed that probiotics improved Hb levels in renal and iron-deficiency anemia, as well as across different doses. The synbiotic group showed consistent efficacy (I² = 0%), while the prebiotic group did not exhibit significant effects, with extremely high heterogeneity (I² = 99.3%). This indicates that heterogeneity may stem from variations in intervention types, and the results should be interpreted with caution.

CONCLUSION

There is moderate-quality evidence suggesting that probiotics, prebiotics, and synbiotics may improve anemia management, particularly by enhancing Hb levels. Further high-quality RCTs are required to explore the specific role of synbiotics in anemia management, including their comparative efficacy against probiotics and prebiotics alone, and their impact on gastrointestinal factors such as gut microbiota modulation and inflammation reduction.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42024590073.

Gut microbiota regulates oxidative stress and inflammation: a double-edged sword in renal fibrosis

Gut microbiota is a complex and dynamic system that plays critical roles in human health and various disease. Progressive chronic kidney disease (CKD) suggests that patients irreversibly progress to end-stage kidney disease and need renal replacement treatments, including dialysis and transplantation. Ample evidence indicates that local oxidative stress and inflammation play pivotal roles in the pathogenesis and progression of CKD and dysbiosis of gut microbiota. CKD is always accompanied by intestinal inflammation and oxidative stress, which lead to rapid systemic translocation of bacterial-derived uraemic toxins, including indoxyl sulphate, phenyl sulphate and indole-3-acetic acid, and the consequent development and aggravation of renal fibrosis. Although inflammation and oxidative stress have been extensively discussed, there is a paucity of reports on the effects of gut microbiota on renal fibrosis and gut microbiota mediation of oxidative stress and inflammation. This review provides an overview of gut microbiota on inflammation and oxidative stress in renal fibrosis, briefly discusses regulation of the gut flora using microecological preparations and natural products, such as resveratrol, curcumin and emodin as treatments for CKD, and provides a clear pathophysiological rationale for the design of promising therapeutic strategies.

Gut Dysbiosis and Its Role in the Anemia of Chronic Kidney Disease

The gut dysbiosis present in chronic kidney disease (CKD) has been associated with anemia. Factors such as the accumulation of gut-derived uremic toxins, increased gut barrier permeability-induced inflammation, and a reduced intestinal production of short-chain fatty acids (SCFAs), all associated with changes in the intestinal microbiota composition in CKD, may lead to the development or worsening of anemia in renal patients. Understanding and addressing these mechanisms related to gut dysbiosis in CKD patients can help to delay the development of anemia and improve its control in this population. One approach is to avoid or reduce the use of drugs linked to gut dysbiosis in CKD, such as phosphate binders, oral iron supplementation, antibiotics, and others, unless they are indispensable. Another approach involves introducing dietary changes that promote a healthier microbiota and/or using prebiotics, probiotics, or symbiotics to improve gut dysbiosis in this setting. These measures can increase the presence of SCFA-producing saccharolytic bacteria and reduce proteolytic bacteria, thereby lowering the production of gut-derived uremic toxins and inflammation. By ameliorating CKD-related gut dysbiosis, these strategies can also improve the control of renal anemia and enhance the response to erythropoiesis-stimulating agents (ESAs) in ESA-resistant patients. In this review, we have explored the relationship between gut dysbiosis in CKD and renal anemia and propose feasible solutions, both those already known and potential future treatments.

Effects of Propolis Supplementation on Gut Microbiota and Uremic Toxin Profiles of Patients Undergoing Hemodialysis

BACKGROUND

Propolis possesses many bioactive compounds that could modulate the gut microbiota and reduce the production of uremic toxins in patients with chronic kidney disease (CKD) undergoing hemodialysis (HD). This clinical trial aimed to evaluate the effects of propolis on the gut microbiota profile and uremic toxin plasma levels in HD patients. These are secondary analyses from a previous double-blind, randomized clinical study, with 42 patients divided into two groups: the placebo and propolis group received 400 mg of green propolis extract/day for eight weeks. Indole-3 acetic acid (IAA), indoxyl sulfate (IS), and p-cresyl sulfate (p-CS) plasma levels were evaluated by reversed-phase liquid chromatography, and cytokines were investigated using the multiplex assay (Bio-Plex Magpix®). The fecal microbiota composition was analyzed in a subgroup of patients (n = 6) using a commercial kit for fecal DNA extraction. The V4 region of the 16S rRNA gene was then amplified by the polymerase chain reaction (PCR) using short-read sequencing on the Illumina NovaSeq PE250 platform in a subgroup. Forty-one patients completed the study, 20 in the placebo group and 21 in the propolis group. There was a positive correlation between IAA and TNF-α (r = 0.53, p = 0.01), IL-2 (r = 0.66, p = 0.002), and between pCS and IL-7 (r = 0.46, p = 0.04) at the baseline. No significant changes were observed in the values of uremic toxins after the intervention. Despite not being significant, microbial evenness and observed richness increased following the propolis intervention. Counts of the Fusobacteria species showed a positive correlation with IS, while counts of Firmicutes, Lentisphaerae, and Proteobacteria phyla were negatively correlated with IS. Two months of propolis supplementation did not reduce the plasma levels of uremic toxins (IAA, IS, and p-CS) or change the fecal microbiota.

The Role of the Gut Microbiota in Complications among Hemodialysis Patients

The composition of the gut microbiota varies among end-stage renal disease (ESRD) patients on the basis of their mode of renal replacement therapy (RRT), with notably more pronounced dysbiosis occurring in those undergoing hemodialysis (HD). Interventions such as dialysis catheters, unstable hemodynamics, strict dietary restrictions, and pharmacotherapy significantly alter the intestinal microenvironment, thus disrupting the gut microbiota composition in HD patients. The gut microbiota may influence HD-related complications, including cardiovascular disease (CVD), infections, anemia, and malnutrition, through mechanisms such as bacterial translocation, immune regulation, and the production of gut microbial metabolites, thereby affecting both the quality of life and the prognosis of patients. This review focuses on alterations in the gut microbiota and its metabolites in HD patients. Additionally, understanding the impact of the gut microbiota on the complications of HD could provide insights into the development of novel treatment strategies to prevent or alleviate complications in HD patients.

The effect of synbiotic supplementation on plasma levels of advanced glycation end products and cardiovascular risk factors in hemodialysis patients: A double-blind clinical trial

There is increasing evidence supporting the relationship between imbalance of gut microbiota and development of chronic kidney and cardiovascular diseases. This study aimed to investigate the effect of synbiotic supplementation on plasma levels of advanced glycation end products (AGEs) and cardiovascular risk factors in hemodialysis (HD) patients. In this randomized, double-blind, placebo-controlled clinical trial, 36 HD patients were randomly allocated into two groups to receive two synbiotic supplements (n = 19) or placebo (n = 17) daily for 12 weeks. Levels of AGEs, fibrinogen, hemoglobin A1c (HbA1c), and other measures were assessed at the beginning and end of the study. The data were analyzed using independent t-tests, paired t-tests, and analysis of covariance (ANCOVA). At the end of the study, the plasma levels of AGEs increased significantly in both the synbiotic (p < .001) and control (p = .001) groups, but the difference between the groups was not significant (p = .272). Plasma levels of fibrinogen decreased specifically within the synbiotic group (p = .007), and a statistically significant disparity between the groups persisted at the study's conclusion (p = .016). The mean levels of blood urea nitrogen (BUN) decreased (p < .05) in both groups, but there was no difference between the two groups at the end of the study (p = .116). No significant differences were observed in other measured biomarkers. Synbiotic supplementation improved plasma fibrinogen and BUN levels in HD patients, but did not significantly improve AGEs and HbA1c. Further investigations are needed to investigate the effect of probiotics on AGEs in HD patients at different stages of kidney disease.

Lactobacillus acidophilus KBL409 protects against kidney injury via improving mitochondrial function with chronic kidney disease

PURPOSE

Recent advances have led to greater recognition of the role of mitochondrial dysfunction in the pathogenesis of chronic kidney disease (CKD). There has been evidence that CKD is also associated with dysbiosis. Here, we aimed to evaluate whether probiotic supplements can have protective effects against kidney injury via improving mitochondrial function.

METHODS

An animal model of CKD was induced by feeding C57BL/6 mice a diet containing 0.2% adenine. KBL409, a strain of Lactobacillus acidophilus, was administered via oral gavage at a dose of 1 × 109 CFU daily. To clarify the underlying mechanisms by which probiotics exert protective effects on mitochondria in CKD, primary mouse tubular epithelial cells stimulated with TGF-β and p-cresyl sulfate were administered with butyrate.

RESULTS

In CKD mice, PGC-1α and AMPK, key mitochondrial energy metabolism regulators, were down-regulated. In addition, mitochondrial dynamics shifted toward fission, the number of fragmented cristae increased, and mitochondrial mass decreased. These alterations were restored by KBL409 administration. KBL409 supplementation also improved defects in fatty acid oxidation and glycolysis and restored the suppressed enzyme levels involved in TCA cycle. Accordingly, there was a concomitant improvement in mitochondrial respiration and ATP production assessed by mitochondrial function assay. These favorable effects of KBL409 on mitochondria ultimately decreased kidney fibrosis in CKD mice. In vitro analyses with butyrate recapitulated the findings of animal study.

CONCLUSIONS

This study demonstrates that administration of the probiotic Lactobacillus acidophilus KBL409 protects against kidney injury via improving mitochondrial function.

Efficacy of probiotics/synbiotics supplementation in patients with chronic kidney disease: a systematic review and meta-analysis of randomized controlled trials

Background

Chronic kidney disease (CKD) is a serious and steadily growing health problem worldwide. Probiotic and synbiotic supplementation are expected to improve kidney function in CKD patients by altering imbalanced intestinal flora, regulating microbiota metabolites, modulating the brain-gut axis, and reducing inflammation.

Objectives

Our aim is to report the latest and largest pooled analyses and evidence updates to explore whether probiotic and synbiotic have beneficial effects on renal function and general conditions in patients with CKD.

Methods

We conducted a systematic literature search using PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials from inception until 1 December 2023. Eligible literatures were screened according to inclusion and exclusion criteria, data were extracted, and a systematic review and meta-analysis was performed. Measurements included renal function-related markers, inflammatory markers, uremic toxins, lipid metabolism-related markers and electrolytes levels.

Results

Twenty-one studies were included. The results showed that probiotic/synbiotic significantly reduced blood urea nitrogen (BUN) (standardized mean difference (SMD), -0.23, 95% confidence interval (CI) -0.41, -0.04; p = 0.02, I2 = 10%) and lowered c-reactive protein level (CRP) (SMD: -0.34; 95% CI: -0.62, -0.07; p = 0.01, I2 = 37%) in CKD patients, compared with the control group.

Conclusion

In summary, probiotic/synbiotic supplementation seems to be effective in improving renal function indices and inflammation indices in CKD patients. Subgroup analyses suggested that longer-term supplementation is more favorable for CKD patients, but there is a high degree of heterogeneity in the results of partial subgroup analyses. The efficacy of probiotic/synbiotic in treating CKD needs to be supported by more evidence from large-scale clinical studies.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42024526836, Unique identifier: CRD42024526836.

The Efficacy and Safety of Probiotic Combinations Lobun Forte® Versus Renadyl® in Patients With Chronic Kidney Disease: A Comparative, Phase IV, Randomized, Open-Label, Active-Controlled, Parallel Study

BACKGROUND

Chronic kidney disease (CKD) often leads to gut microbiota imbalance, accelerating disease progression and increasing uremic toxins and inflammation. We conducted a randomized clinical trial comparing outcomes between two multi-strain probiotic supplements Lobun Forte® (Sanzyme P Ltd, Hyderabad, India) containing Streptococcus thermophilus, Lactobacillus acidophilus, Bifidobacterium longum, and Bacillus coagulans and Renadyl® (Kibow Biotech, LLC., Pennsylvania, United States) containing S. thermophilus, L. acidophilus, and B. longum.

MATERIALS AND METHODS

Sixty patients with stage 3-4 CKD were randomized to receive either Lobun Forte (n=30) or Renadyl (n=30) for six months, with each supplement providing 45 billion CFU/capsule, twice daily. Primary outcomes included quality of life (QoL) (Short-Form 8 (SF-8) score), reductions in uremic toxins (p-cresyl sulfate (PCS), 3-indoxyl sulfate (IS), indole-3-acetic acid (IAA)), blood urea nitrogen (BUN), serum creatinine, and serum uric acid. Secondary outcomes assessed oxidative stress, inflammatory biomarkers, and estimated glomerular filtration rate (eGFR). Results: Both Lobun Forte and Renadyl groups showed significant improvements in QoL, with Lobun Forte achieving a 53.5% improvement (16.43 point increase) and Renadyl a 51.1% improvement (15.27 point increase) in SF-8 scores (p < 0.0001). The levels of IS decreased significantly in both groups (p < 0.0001), with Lobun Forte reducing IS by 29.72% and Renadyl by 24.20%. In terms of other uremic toxins, Lobun Forte showed non-significant (p > 0.05) reductions in mean PCS (7.63%) and IAA (15.57%), whereas Renadyl demonstrated a significant (p = 0.0314) decrease in PCS (20.75%) and a non-significant (p > 0.05) reduction in IAA (12.35%). Both groups showed significant (p < 0.0001) reductions in BUN and serum creatinine levels. Serum uric acid levels showed a significant (p = 0.0448) reduction with Lobun Forte while Renadyl exhibited a non-significant reduction (p = 0.1034). Lobun Forte significantly (p = 0.0359) reduced mean high-sensitivity C-reactive protein (hsCRP) levels, while Renadyl showed a non-significant reduction (p = 0.0876). Both groups had non-significant reductions in interleukin-6 and tumor necrosis factor-alpha levels (p > 0.05). Further, both groups experienced significant (p < 0.0001) increases in mean glutathione levels and nitric oxide levels. Additionally, Renadyl resulted in a significant reduction in mean malondialdehyde, whereas Lobun Forte showed a non-significant reduction. Both probiotics significantly (p < 0.0001) improved eGFR, with Lobun Forte increasing it by 40.4% and Renadyl by 36.9%. Both probiotics were well tolerated, with a favorable safety profile throughout the study. Conclusion: Both Lobun Forte and Renadyl effectively improve the quality of life in patients with stage 3-4 CKD by modulation of uremic toxins, renal parameters, inflammatory biomarkers, oxidative biomarkers, and eGFR. These findings suggest that both probiotics may help delay CKD progression by modulating the gut-kidney axis.

A Symbiotic Meal Containing Extruded Sorghum and Probiotic (Bifidobacterium longum) Ameliorated Intestinal Health Markers in Individuals with Chronic Kidney Disease: A Secondary Analysis of a Subsample from a Previous Randomized and Controlled Clinical Trial

BACKGROUND

Chronic kidney disease increases uremic toxins concentrations, which have been associated with intestinal dysbiosis. Sorghum bicolor L. Moench has dietary fiber and bioactive compounds, while Bifidobacterium longum can promote beneficial health effects.

METHODS

It is a controlled, randomized, and single-blind clinical trial. Thirty-nine subjects were randomly separated into two groups: symbiotic group (SG), which received 100 mL of unfermented probiotic milk with Bifidobacterium longum strain and 40 g of extruded sorghum flakes; and the control group (CG), which received 100 mL of pasteurized milk and 40 g of extruded corn flakes for seven weeks.

RESULTS

The uremic toxins decreased, and gastrointestinal symptoms improved intragroup in the SG group. The acetic, propionic, and butyric acid production increased intragroup in the SG group. Regarding α-diversity, the Chao1 index was enhanced in the SG intragroup. The KEGG analysis revealed that symbiotic meal increased the intragroup energy and amino sugar metabolism, in addition to enabling essential amino acid production and metabolism, sucrose degradation, and the biosynthesis of ribonucleotide metabolic pathways.

CONCLUSIONS

The consumption of symbiotic meal reduced BMI, improved short-chain fatty acid (SCFA) synthesis and gastrointestinal symptoms, increased diversity according to the Chao1 index, and reduced uremic toxins in chronic kidney disease patients.

Probiotic-driven advancement: Exploring the intricacies of mineral absorption in the human body

The interplay between probiotics and mineral absorption is a topic of growing interest due to its great potential for human well-being. Minerals are vital in various physiological processes, and deficiencies can lead to significant health problems. Probiotics, beneficial microorganisms residing in the gut, have recently gained attention for their ability to modulate mineral absorption and mitigate deficiencies. The aim of the present review is to investigate the intricate connection between probiotics and the absorption of key minerals such as calcium, selenium, zinc, magnesium, and potassium. However, variability in probiotic strains, and dosages, alongside the unique composition of individuals in gut microbiota, pose challenges in establishing universal guidelines. An improved understanding of these mechanisms will enable the development of targeted probiotic interventions to optimize mineral absorption and promote human health.

Septic acute kidney injury and gut microbiome: Should we change our approach?

Incidence of acute kidney injury (AKI) remained relatively stable over the last decade and the adjusted risks for it and mortality are similar across different continents and regions. Also, the mortality of septic-AKI can reach 70% in critically-ill patients. These sole facts can give rise to a question: is there something we do not understand yet? Currently, there are no specific therapies for septic AKI and the treatment aims only to maintain the mean arterial pressure over 65mmHg by ensuring a good fluid resuscitation and by using vasopressors, along with antibiotics. On the other hand, there is an increased concern about the different hemodynamic changes in septic AKI versus other forms and the link between the gut microbiome and the severity of septic AKI. Fortunately, progress has been made in the form of administration of pre- and probiotics, short chain fatty acids (SCFA), especially acetate, and also broad-spectrum antibiotics or selective decontaminants of the digestive tract in a successful attempt to modulate the microbial flora and to decrease both the severity of AKI and mortality. In conclusion, septic-AKI is a severe form of kidney injury, with particular hemodynamic changes and with a strong link between the kidney and the gut microbiome. By modulating the immune response we could not only treat but also prevent severe forms. The most difficult part is to categorize patients and to better understand the key mechanisms of inflammation and cellular adaptation to the injury, as these mechanisms can serve in the future as target therapies.

An Overview of Chronic Kidney Disease Pathophysiology: The Impact of Gut Dysbiosis and Oral Disease

Chronic kidney disease (CKD) is a severe condition and a significant public health issue worldwide, carrying the burden of an increased risk of cardiovascular events and mortality. The traditional factors that promote the onset and progression of CKD are cardiometabolic risk factors like hypertension and diabetes, but non-traditional contributors are escalating. Moreover, gut dysbiosis, inflammation, and an impaired immune response are emerging as crucial mechanisms in the disease pathology. The gut microbiome and kidney disease exert a reciprocal influence commonly referred to as "the gut-kidney axis" through the induction of metabolic, immunological, and endocrine alterations. Periodontal diseases are strictly involved in the gut-kidney axis for their impact on the gut microbiota composition and for the metabolic and immunological alterations occurring in and reciprocally affecting both conditions. This review aims to provide an overview of the dynamic biological interconnections between oral health status, gut, and renal pathophysiology, spotlighting the dynamic oral-gut-kidney axis and raising whether periodontal diseases and gut microbiota can be disease modifiers in CKD. By doing so, we try to offer new insights into therapeutic strategies that may enhance the clinical trajectory of CKD patients, ultimately advancing our quest for improved patient outcomes and well-being.

Synbiotics, prebiotics and probiotics for people with chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is a major public health problem affecting 13% of the global population. Prior research has indicated that CKD is associated with gut dysbiosis. Gut dysbiosis may lead to the development and/or progression of CKD, which in turn may in turn lead to gut dysbiosis as a result of uraemic toxins, intestinal wall oedema, metabolic acidosis, prolonged intestinal transit times, polypharmacy (frequent antibiotic exposures) and dietary restrictions used to treat CKD. Interventions such as synbiotics, prebiotics, and probiotics may improve the balance of the gut flora by altering intestinal pH, improving gut microbiota balance and enhancing gut barrier function (i.e. reducing gut permeability).

OBJECTIVES

This review aimed to evaluate the benefits and harms of synbiotics, prebiotics, and probiotics for people with CKD.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 9 October 2023 through contact with the Information Specialist using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Registry Platform (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) measuring and reporting the effects of synbiotics, prebiotics, or probiotics in any combination and any formulation given to people with CKD (CKD stages 1 to 5, including dialysis and kidney transplant). Two authors independently assessed the retrieved titles and abstracts and, where necessary, the full text to determine which satisfied the inclusion criteria.

DATA COLLECTION AND ANALYSIS

Data extraction was independently carried out by two authors using a standard data extraction form. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) or standardised mean difference (SMD) and 95% CI for continuous outcomes. The methodological quality of the included studies was assessed using the Cochrane risk of bias tool. Data entry was carried out by one author and cross-checked by another. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

Forty-five studies (2266 randomised participants) were included in this review. Study participants were adults (two studies in children) with CKD ranging from stages 1 to 5, with patients receiving and not receiving dialysis, of whom half also had diabetes and hypertension. No studies investigated the same synbiotic, prebiotic or probiotic of similar strains, doses, or frequencies. Most studies were judged to be low risk for selection bias, performance bias and reporting bias, unclear risk for detection bias and for control of confounding factors, and high risk for attrition and other biases. Compared to prebiotics, it is uncertain whether synbiotics improve estimated glomerular filtration rate (eGFR) at four weeks (1 study, 34 participants: MD -3.80 mL/min/1.73 m², 95% CI -17.98 to 10.38), indoxyl sulfate at four weeks (1 study, 42 participants: MD 128.30 ng/mL, 95% CI -242.77 to 499.37), change in gastrointestinal (GI) upset (borborymgi) at four weeks (1 study, 34 participants: RR 15.26, 95% CI 0.99 to 236.23), or change in GI upset (Gastrointestinal Symptom Rating Scale) at 12 months (1 study, 56 participants: MD 0.00, 95% CI -0.27 to 0.27), because the certainty of the evidence was very low. Compared to certain strains of prebiotics, it is uncertain whether a different strain of prebiotics improves eGFR at 12 weeks (1 study, 50 participants: MD 0.00 mL/min, 95% CI -1.73 to 1.73), indoxyl sulfate at six weeks (2 studies, 64 participants: MD -0.20 μg/mL, 95% CI -1.01 to 0.61; I² = 0%) or change in any GI upset, intolerance or microbiota composition, because the certainty of the evidence was very low. Compared to certain strains of probiotics, it is uncertain whether a different strain of probiotic improves eGFR at eight weeks (1 study, 30 participants: MD -0.64 mL/min, 95% CI -9.51 to 8.23; very low certainty evidence). Compared to placebo or no treatment, it is uncertain whether synbiotics improve eGFR at six or 12 weeks (2 studies, 98 participants: MD 1.42 mL/min, 95% CI 0.65 to 2.2) or change in any GI upset or intolerance at 12 weeks because the certainty of the evidence was very low. Compared to placebo or no treatment, it is uncertain whether prebiotics improves indoxyl sulfate at eight weeks (2 studies, 75 participants: SMD -0.14 mg/L, 95% CI -0.60 to 0.31; very low certainty evidence) or microbiota composition because the certainty of the evidence is very low. Compared to placebo or no treatment, it is uncertain whether probiotics improve eGFR at eight, 12 or 15 weeks (3 studies, 128 participants: MD 2.73 mL/min, 95% CI -2.28 to 7.75; I² = 78%), proteinuria at 12 or 24 weeks (1 study, 60 participants: MD -15.60 mg/dL, 95% CI -34.30 to 3.10), indoxyl sulfate at 12 or 24 weeks (2 studies, 83 participants: MD -4.42 mg/dL, 95% CI -9.83 to 1.35; I² = 0%), or any change in GI upset or intolerance because the certainty of the evidence was very low. Probiotics may have little or no effect on albuminuria at 12 or 24 weeks compared to placebo or no treatment (4 studies, 193 participants: MD 0.02 g/dL, 95% CI -0.08 to 0.13; I² = 0%; low certainty evidence). For all comparisons, adverse events were poorly reported and were minimal (flatulence, nausea, diarrhoea, abdominal pain) and non-serious, and withdrawals were not related to the study treatment.

AUTHORS' CONCLUSIONS

We found very few studies that adequately test biotic supplementation as alternative treatments for improving kidney function, GI symptoms, dialysis outcomes, allograft function, patient-reported outcomes, CVD, cancer, reducing uraemic toxins, and adverse effects. We are not certain whether synbiotics, prebiotics, or probiotics are more or less effective compared to one another, antibiotics, or standard care for improving patient outcomes in people with CKD. Adverse events were uncommon and mild.

Lactobacillus rhamnosus GG aggravates vascular calcification in chronic kidney disease: A potential role for extracellular vesicles

AIMS

Lactobacillus rhamnosus GG (LGG) is a probiotic with great promise in future clinical application, which can significantly promote bone formation. However, the effect of LGG on CKD-related vascular calcification is unclear. In this study, we aimed to investigate the effect of LGG on CKD-related vascular calcification.

MATERIALS AND METHODS

After 2 weeks of 5/6 nephrectomy, CKD rats received a special diet (4 % calcium and 1.8 % phosphate) combined with 1,25-dihydroxyvitamin D3 to induce vascular calcification. Meanwhile, CKD rats in the LGG group were gavaged orally with LGG (1 × 109 CFU bacteria/day). 16S RNA amplicon sequencing was performed to analyze the effect of LGG treatment on gut microbiota composition. Furthermore, differential ultracentrifugation was utilized to extract EVs. The effects of EVs on vascular calcification were evaluated in rat VSMCs, rat aortic rings, and CKD rat calcification models. In this study, vascular calcification was assessed by microcomputed tomography analysis, alizarin red staining, calcium content determination, and the expression of osteogenic transcription factors RUNX2 and BMP2.

KEY FINDINGS

LGG remarkably aggravated vascular calcification. LGG supplementation significantly altered gut microbiota composition in CKD rats, particularly increasing Lactobacillus. Interestingly, EVs presented a significant promoting effect on the development of calcification. Finally, mechanistic analysis proved that EVs aggravated vascular calcification through PI3K/AKT signaling.

SIGNIFICANCE

These results do not support the supplementation of LGG in CKD-associated vascular calcification patients. Our study presented a fresh perspective on LGG with potential risks and adverse effects. CKD patients should use specific probiotic strains cautiously.

Gut Microbiota Interventions to Retain Residual Kidney Function

Residual kidney function for patients with chronic kidney disease (CKD) is associated with better quality of life and outcome; thus, strategies should be implemented to preserve kidney function. Among the multiple causes that promote kidney damage, gut dysbiosis due to increased uremic toxin production and endotoxemia need attention. Several strategies have been proposed to modulate the gut microbiota in these patients, and diet has gained increasing attention in recent years since it is the primary driver of gut dysbiosis. In addition, medications and faecal transplantation may be valid strategies. Modifying gut microbiota composition may mitigate chronic kidney damage and preserve residual kidney function. Although various studies have shown the influential role of diet in modulating gut microbiota composition, the effects of this modulation on residual kidney function remain limited. This review discusses the role of gut microbiota metabolism on residual kidney function and vice versa and how we could preserve the residual kidney function by modulating the gut microbiota balance.

The role of probiotics in tissue engineering and regenerative medicine

Tissue engineering and regenerative medicine (TERM) as an emerging field is a multidisciplinary science and combines basic sciences such as biomaterials science, biology, genetics and medical sciences to achieve functional TERM-based products to regenerate or replace damaged or diseased tissues or organs. Probiotics are useful microorganisms which have multiple effective functions on human health. They have some immunomodulatory and biocompatibility effects and improve wound healing. In this article, we describe the latest findings on probiotics and their pro-healing properties on various body systems that are useable in regenerative medicine. Therefore, this review presents a new perspective on the therapeutic potential of probiotics for TERM.

Functional profile and encapsulating properties of Colocasia esculenta (Taro)

Especially in tropical and subtropical countries, tuber and root crops have developed into important food crops. Due to its use in food preparation, aesthetics, and medicine, taro (Colocasia esculenta) is ranked as the fifth most important root crop. In comparison, it stores a considerable quantity of starch - even more than potatoes, sweet potatoes, cassava, and other similar crops. Colocasia leaves are lower in calories and high in dietary fiber minerals and proteins. The corms of Colocasia antiquorum contain anthocyanins such as pelargonidin-3-glucoside, cyanidin-3-glucoside, and cyanidin-3-chemnoside, which are reported to possess antifungal and antioxidative characteristics. The underground corms of taro (Colocasia esculenta), which contain 70%-80% starch, are the primary reason for its cultivation. Taro is a highly digestible root vegetable with a high content of mucilaginous gums and trivial starchy granules. It is used to make a variety of dishes. This review article highlights the functional properties, phytochemical profile, encapsulating properties, and various industrial applications. Its health advantages and dietary uses were also addressed.

The Impact of Synbiotic Treatment on the Levels of Gut-Derived Uremic Toxins, Inflammation, and Gut Microbiome of Chronic Kidney Disease Patients-A Randomized Trial

OBJECTIVE

Altering dysbiotic gut flora through synbiotic supplementation has recently been recognized as a potential treatment strategy to reduce the levels of gut-derived uremic toxins and decrease inflammation. Assessing its efficacy and safety has been the main goal of our randomized, double-blind, placebo-controlled study.

METHODS

A total of 34 nondialyzed chronic kidney disease patients, aged ≥18 years, with an estimated glomerular filtration rate between 15 and 45 mL/minute, were randomized either to an intervention group (n = 17), receiving synbiotic (Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium lactis, 32 billion colony forming units per day plus 3.2 g of inulin), or control group (n = 17), receiving placebo during 12 weeks. The impact of treatment on the dynamic of serum levels of gut-derived uremic toxins, total serum indoxyl sulfate, p-cresyl sulfate, and trimethylamine N-oxide, was defined as the primary outcome of the study. Secondary outcomes included changes in the stool microbiome, serum interleukin-6 levels, high-sensitivity C-reactive protein, estimated glomerular filtration rate, albuminuria, diet, gastrointestinal symptom dynamics, and safety. Serum levels of uremic toxins were determined using ultraperformance liquid chromatography. The stool microbiome analysis was performed using the 16S ribosomal ribonucleic acid gene sequencing approach.

RESULTS

Synbiotic treatment significantly modified gut microbiome with Bifidobacteria, Lactobacillus, and Subdoligranulum genera enrichment and consequently reduced serum level of indoxyl sulfate (ΔIS -21.5% vs. 5.3%, P < .001), improved estimated glomerular filtration rate (ΔeGFR 12% vs. 8%, P = .029), and decreased level of high-sensitivity C-reactive protein (-39.5 vs. -8.5%, P < .001) in treated patients. Two patients of the intervention arm complained of increased flatulence. No other safety issues were noted.

CONCLUSION

Synbiotics could be available, safe, and an effective therapeutic strategy we could use in daily practice in order to decrease levels of uremic toxins and microinflammation in chronic kidney disease patients.

Gut Microbiota in Chronic Kidney Disease: From Composition to Modulation towards Better Outcomes-A Systematic Review

BACKGROUND

A bidirectional kidney-gut axis was described in patients with chronic kidney disease (CKD). On the one hand, gut dysbiosis could promote CKD progression, but on the other hand, studies reported specific gut microbiota alterations linked to CKD. Therefore, we aimed to systematically review the literature on gut microbiota composition in CKD patients, including those with advanced CKD stages and end-stage kidney disease (ESKD), possibilities to shift gut microbiota, and its impact on clinical outcomes.

MATERIALS AND METHODS

We performed a literature search in MEDLINE, Embase, Scopus, and Cochrane databases to find eligible studies using pre-specified keywords. Additionally, key inclusion and exclusion criteria were pre-defined to guide the eligibility assessment.

RESULTS

We retrieved 69 eligible studies which met all inclusion criteria and were analyzed in the present systematic review. Microbiota diversity was decreased in CKD patients as compared to healthy individuals. Ruminococcus and Roseburia had good power to discriminate between CKD patients and healthy controls (AUC = 0.771 and AUC = 0.803, respectively). Roseburia abundance was consistently decreased in CKD patients, especially in those with ESKD (p < 0.001). A model based on 25 microbiota dissimilarities had an excellent predictive power for diabetic nephropathy (AUC = 0.972). Several microbiota patterns were observed in deceased ESKD patients as compared to the survivor group (increased Lactobacillus, Yersinia, and decreased Bacteroides and Phascolarctobacterium levels). Additionally, gut dysbiosis was associated with peritonitis and enhanced inflammatory activity. In addition, some studies documented a beneficial effect on gut flora composition attributed to synbiotic and probiotic therapies. Large randomized clinical trials are required to investigate the impact of different microbiota modulation strategies on gut microflora composition and subsequent clinical outcomes.

CONCLUSIONS

Patients with CKD had an altered gut microbiome profile, even at early disease stages. Different abundance at genera and species levels could be used in clinical models to discriminate between healthy individuals and patients with CKD. ESKD patients with an increased mortality risk could be identified through gut microbiota analysis. Modulation therapy studies are warranted.

Food-Derived Uremic Toxins in Chronic Kidney Disease

Patients with chronic kidney disease (CKD) have a higher cardiovascular risk compared to the average population, and this is partially due to the plasma accumulation of solutes known as uremic toxins. The binding of some solutes to plasma proteins complicates their removal via conventional therapies, e.g., hemodialysis. Protein-bound uremic toxins originate either from endogenous production, diet, microbial metabolism, or the environment. Although the impact of diet on uremic toxicity in CKD is difficult to quantify, nutrient intake plays an important role. Indeed, most uremic toxins are gut-derived compounds. They include Maillard reaction products, hippurates, indoles, phenols, and polyamines, among others. In this review, we summarize the findings concerning foods and dietary components as sources of uremic toxins or their precursors. We then discuss their endogenous metabolism via human enzyme reactions or gut microbial fermentation. Lastly, we present potential dietary strategies found to be efficacious or promising in lowering uremic toxins plasma levels. Aligned with current nutritional guidelines for CKD, a low-protein diet with increased fiber consumption and limited processed foods seems to be an effective treatment against uremic toxins accumulation.

Natural products from plants and microorganisms: Novel therapeutics for chronic kidney disease via gut microbiota regulation

Dysbiosis of gut microbiota plays a fundamental role in the pathogenesis and development of chronic kidney disease (CKD) and its complications. Natural products from plants and microorganisms can achieve recognizable improvement in renal function and serve as an alternative treatment for chronic kidney disease patients with a long history, yet less is known on its beneficial effects on kidney injury by targeting the intestinal microbiota. In this review, we summarize studies on the effects of natural products from plants and microorganisms, including herbal medicines and their bioactive extracts, polysaccharides from plants and microorganisms, and phytochemicals, on the prevention and treatment of chronic kidney disease through targeting gut microflora. We describe the strategies of these anti-CKD effects in animal experiments including remodulation of gut microbiota structure, reduction of uremic toxins, enhancement of short-chain fatty acid (SCFA) production, regulation of intestinal inflammatory signaling, and improvement in intestinal integrity. Meanwhile, the clinical trials of different natural products in chronic kidney disease clinical practice were also analyzed and discussed. These provide information to enable a better understanding of the renoprotective effects of these effective natural products from plants and microorganisms in the treatment of chronic kidney disease. Finally, we propose the steps to prove the causal role of the intestinal microflora in the treatment of chronic kidney disease by natural products from plants and microorganisms. We also assess the future perspective that natural active products from plants and microorganisms can beneficially delay the onset and progression of kidney disease by targeting the gut flora and highlight the remaining challenges in this area. With the continuous deepening of studies in recent years, it has been proved that gut microbiota is a potential target of natural active products derived from plants and microorganisms for chronic kidney disease treatment. Fully understanding the functions and mechanisms of gut microbiota in these natural active products from plants and microorganisms is conducive to their application as an alternative therapeutic in the treatment of chronic kidney disease.

Probiotics, Prebiotics, and Synbiotics for Patients on Dialysis: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

The current systematic review and meta-analysis investigated the effects of probiotic, prebiotic, and synbiotic administration on inflammation, metabolic parameters, nutritional status, and uremic toxin in dialysis patients.

METHODS

Up to June 2021, publications were searched in Cochrane Library, PubMed, EMBASE, and Web of Science databases. The protocol was submitted to the International Prospective Register of Systematic Reviews and was approved.

RESULTS

This meta-analysis included 18 randomized controlled trials which were eligible. This meta-analysis discovered that probiotic, prebiotic, and synbiotic supplements could reduce C-reactive protein (standardized mean difference (SMD), -0.38; 95% confidence interval (CI), -0.68 to -0.08; P = .01), interleukin 6 (SMD, -0.48; 95% CI, -0.76 to -0.20; P = .00), and indoxyl sulfate (SMD, -0.24; 95% CI, -0.48 to -0.01; P = .045) and increase high-density lipoprotein cholesterol (SMD, 0.25; 95% CI, 0.03 to 0.46; P = .025) compared with the control group but had no significant influence on tumor necrosis factor α, albumin, hemoglobin, triglyceride, total cholesterol, low-density lipoprotein cholesterol, calcium, phosphorus, uric acid, or p-cresyl sulfate in dialysis patients.

CONCLUSIONS

Probiotic, prebiotic, and synbiotic administration could reduce C-reactive protein, interleukin 6, and indoxyl sulfate and increase high-density lipoprotein cholesterol in dialysis patients. To better examine the impact, large-scale, long-term, controlled diets and well-designed randomized controlled trials are needed.

Uremic toxins in chronic kidney disease highlight a fundamental gap in understanding their detrimental effects on cardiac electrophysiology and arrhythmogenesis

Chronic kidney disease (CKD) and cardiovascular disease (CVD) have an estimated 700-800 and 523 million cases worldwide, respectively, with CVD being the leading cause of death in CKD patients. The pathophysiological interplay between the heart and kidneys is defined as the cardiorenal syndrome (CRS), in which worsening of kidney function is represented by increased plasma concentrations of uremic toxins (UTs), culminating in dialysis patients. As there is a high incidence of CVD in CKD patients, accompanied by arrhythmias and sudden cardiac death, knowledge on electrophysiological remodeling would be instrumental for understanding the CRS. While the interplay between both organs is clearly of importance in CRS, the involvement of UTs in pro-arrhythmic remodeling is only poorly investigated, especially regarding the mechanistic background. Currently, the clinical approach against potential arrhythmic events is mainly restricted to symptom treatment, stressing the need for fundamental research on UT in relation to electrophysiology. This review addresses the existing knowledge of UTs and cardiac electrophysiology, and the experimental research gap between fundamental research and clinical research of the CRS. Clinically, mainly absorbents like ibuprofen and AST-120 are studied, which show limited safe and efficient usability. Experimental research shows disturbances in cardiac electrical activation and conduction after inducing CKD or exposure to UTs, but are scarcely present or focus solely on already well-investigated UTs. Based on UTs data derived from CKD patient cohort studies, a clinically relevant overview of physiological and pathological UTs concentrations is created. Using this, future experimental research is stimulated to involve electrophysiologically translatable animals, such as rabbits, or in vitro engineered heart tissues.

The Potential Benefits and Controversies of Probiotics Use in Patients at Different Stages of Chronic Kidney Disease

The therapeutic modulation of the gut microbiome has been suggested to be one of the tools in the integrated management of chronic kidney disease (CKD) in recent years. Lactobacillus and Bifidobacterium genera are the two most commonly used probiotics strains. Most of the probiotics used in studies are mixed formulation. There is no consensus on the dose and duration of the probiotic administration for CKD patients Increasing evidence indicates that patients with early stage (1-2) CKD have an altered quantitative and qualitative microbiota profile. However, there was a dearth of prospective controlled studies on the use of probiotics in the early stage of the CKD population. The association between gut microbiota disturbance and advanced CKD was reported. Most randomized controlled trials on probiotic treatment used in CKD stage 3-5ND patients reported positive results. The metabolites of abnormal gut microbiota are directly involved in the pathogenetic mechanisms of cardiovascular disease and inflammation. We summarized 13 studies performed in the dialysis population, including 10 in hemodialysis (HD) patients and 3 in peritoneal dialysis (PD). Some controversial results were concluded on the decreasing plasma concentration of uremic toxin, symptoms, inflammation, and cardiovascular risk. Only three randomized controlled trials on PD were reported to show the potential beneficial effects of probiotics on inflammation, uremic toxins and gastrointestinal symptoms. There is still no standard in the dosage and duration of the use of probiotics in CKD patients. Overall, the probiotic administration may have potential benefit in improving symptoms and quality of life, reducing inflammation, and delaying the progression of kidney failure. Further research studies using a larger sample size with longer follow-up durations and a greater focus on clinical outcomes-including survival-are warranted to elucidate the significant clinical impact of the use of probiotics in CKD patients.

Enzobiotics-A Novel Therapy for the Elimination of Uremic Toxins in Patients with CKD (EETOX Study): A Multicenter Double-Blind Randomized Controlled Trial

Design, participants, setting, and measurements: Predialysis adult participants with chronic kidney disease (CKD) and mean estimated glomerular filtration rate (eGFR) <45 mL/min per 1.73 m2) were recruited in 2019 to a multicentric double-blinded randomized controlled trial of enzobiotic therapy (synbiotics and proteolytic enzymes) conducted over 12 weeks. The primary objective was to evaluate the efficacy and safety of enzobiotics in reducing the generation of p-cresol sulfate (PCS) and indoxyl sulfate (IS), stabilizing renal function, and improving quality of life (QoL), while the secondary objective was to evaluate the feasibility of the diagnostic prediction of IS and PCS from CKD parameters. Results: Of the 85 patients randomized (age 48.76 years, mean eGFR 23.24 mL/min per 1.73 m2 in the placebo group; age 54.03 years, eGFR 28.93 mL/min per 1.73 m2 in the enzobiotic group), 50 completed the study. The absolute mean value of PCS increased by 12% from 19 µg/mL (Day 0) to 21 µg/mL (Day90) for the placebo group, whereas it decreased by 31% from 23 µg/mL (Day 0) to 16 µg/mL (Day 90) for the enzobiotic group. For IS, the enzobiotic group showed a decrease (6.7%) from 11,668 to 10,888 ng/mL, whereas the placebo group showed an increase (8.8%) from 11,462 to 12,466 ng/mL (Day 90). Each patient improvement ratio for Day 90/Day 0 analysis showed that enzobiotics reduced PCS by 23% (0.77, p = 0.01). IS levels remained unchanged. In the placebo group, PCS increased by 27% (1.27, p = 0.14) and IS increased by 20% (1.20, p = 0.14). The proportion of individuals beyond the risk threshold for PCS (>20 µg/mL) was 53% for the placebo group and 32% for the enzobiotic group. The corresponding levels for IS risk (threshold >20,000 ng/mL) were 35% and 24% for the placebo and enzobiotic groups, respectively. In the placebo group, eGFR decreased by 7% (Day 90) but remained stable (1.00) in the enzobiotic group. QoL as assessed by the adversity ratio decreased significantly (p = 0.00), highlighting an improvement in the enzobiotic group compared to the placebo group. The predictive equations were as follows: PCS (Day 0 = −5.97 + 0.0453 PC + 2.987 UA − 1.310 Creat; IS (Day 0) = 756 + 1143 Creat + 436.0 Creat2. Conclusion: Enzobiotics significantly reduced the PCS and IS, as well as improved the QoL.

Effectiveness of Microecological Preparations for Improving Renal Function and Metabolic Profiles in Patients With Chronic Kidney Disease

Background

Determining whether microecological preparations, including probiotics, prebiotics, and synbiotics, are beneficial for patients with chronic kidney disease (CKD) has been debated. Moreover, determining which preparation has the best effect remains unclear. In this study, we performed a network meta-analysis of randomized clinical trials (RCTs) to address these questions.

Methods

MEDLINE, EMBASE, PubMed, Web of Science, and the Cochrane Central Register of Controlled Trials were searched. Eligible RCTs with patients with CKD who received intervention measures involving probiotics, prebiotics, and/or synbiotics were included. The outcome indicators included changes in renal function, lipid profiles, inflammatory factors, and oxidative stress factors.

Results

Twenty-eight RCTs with 1,373 patients were ultimately included. Probiotics showed greater effect in lowering serum creatinine [mean difference (MD) -0.21, 95% confidence interval (CI) -0.34, -0.09] and triglycerides (MD -9.98, 95% CI -19.47, -0.49) than the placebo, with the largest surface area under the cumulative ranking curve, while prebiotics and synbiotics showed no advantages. Probiotics were also able to reduce malondialdehyde (MDA) (MD -0.54, 95% CI -0.96, -0.13) and increase glutathione (MD 72.86, 95% CI 25.44, 120.29). Prebiotics showed greater efficacy in decreasing high-sensitivity C-reactive protein (MD -2.06, 95% CI -3.79, -0.32) and tumor necrosis factor-α (MD -2.65, 95% CI -3.91, -1.39). Synbiotics showed a partially synergistic function in reducing MDA (MD -0.66, 95% CI -1.23, -0.09) and high-sensitivity C-reactive protein (MD -2.01, 95% CI -3.87, -0.16) and increasing total antioxidant capacity (MD 145.20, 95% CI 9.32, 281.08).

Conclusion

The results indicated that microbial supplements improved renal function and lipid profiles and favorably affected measures of oxidative stress and inflammation in patients with CKD. After thorough consideration, probiotics provide the most comprehensive and beneficial effects for patients with CKD and might be used as the best choice for microecological preparations.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022295497, PROSPERO 2022, identifier: CRD42022295497.

Food for healthier aging: power on your plate

Inflammageing is a persistent low-level inflammatory burden that accompanies age-related dysregulation of the immune system during normative aging and within the diseasome of aging. A healthy diet containing a balanced amount of macronutrients, vitamins and minerals, adequate in calories and rich in poly(phenols), has an essential role in mitigating the effects of inflammageing and extending healthspan through modulation of the activity of a range of factors. These include transcription factors, such as nuclear factor erythroid-derived 2 related factor 2 (Nrf2) and nuclear factor-κB (NF-kB), the inflammasome and the activities of the gut microbiota. The aim of this narrative review is to discuss the potential of food to ameliorate the effects of the diseasome of aging.

TMAO as a potential biomarker and therapeutic target for chronic kidney disease: A review

The gut microbiota and its metabolites have become a hotspot of recent research. Trimethylamine N-oxide (TMAO) metabolized by the gut microbiota is closely related to many diseases such as cardiovascular disease, chronic kidney disease, type 2 diabetes, etc. Chronic kidney disease (CKD) is an important contributor to morbidity and mortality from non-communicable diseases. Recently, increasing focus has been put on the role of TMAO in the development and progress of chronic kidney disease. The level of TMAO in patients with chronic kidney disease is significantly increased, and a high level of TMAO deteriorates chronic kidney disease. This article describes the relationship between TMAO and chronic kidney disease and the research progress of drugs targeted TMAO, providing a reference for the development of anti-chronic kidney disease drugs targeted TMAO.

Effects of Microbiota-Driven Therapy on Circulating Indoxyl Sulfate and P-Cresyl Sulfate in Patients with Chronic Kidney Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Indoxyl sulfate (IS) and p-cresyl sulfate (PCS), protein-bound uremic toxins, exacerbate the deterioration of renal function and increase the risk of cardiovascular events in chronic kidney disease (CKD) patients. The effects of microbiota-driven therapy (probiotics, prebiotics, or synbiotics) on decreasing circulating IS and PCS concentrations are controversial; thus, we performed the present systematic review and meta-analysis to assess the effects of microbiota-driven therapy on circulating IS and PCS concentrations in CKD patients. PubMed, EMBASE, and Cochrane Library databases were systematically searched from inception to 22 July, 2021, and randomized controlled trials (RCTs) investigating the effects of microbiota-driven therapy on circulating IS and PCS concentrations in CKD patients were included. In all, 14 RCTs with 513 participants were eligible for the meta-analysis. The effects of microbiota-driven therapy on the circulating IS and PCS concentrations were evaluated with weighted mean differences (WMDs) measured by a fixed-effects model or a random-effects model. Compared with placebo, microbiota-driven therapy had no statistically significant effect on the circulating IS concentration (WMD: -1.64 mg/L; 95% CI: -3.46, 0.18 mg/L; P = 0.077) but it decreased the circulating PCS concentration (WMD: -2.42 mg/L; 95% CI: -3.81, -1.04 mg/L; P = 0.001). In the subgroup analyses, prebiotic (n = 6) and synbiotic (n = 3) supplementation significantly decreased the circulating PCS concentration, whereas probiotic (n = 3) supplementation did not. Meta-regression showed that the effects of microbiota-driven therapy were not associated with the supplementation time or the year of publication. Moreover, there was no significant evidence of publication bias. This review found that microbiota-driven therapy decreased the circulating PCS concentration in CKD patients. Additional large, well-designed RCTs with improved methodology and reporting are necessary to assess the effects of microbiota-driven therapy on circulating IS and PCS concentrations in the long term. This systematic review was registered at www.crd.york.ac.uk/prospero/ as CRD42021269146.

Metabolomic Profile of Different Dietary Patterns and Their Association with Frailty Index in Community-Dwelling Older Men and Women

Diet quality has been associated with slower rates of aging; however, the mechanisms underlying the role of a healthy diet in aging are not fully understood. To address this question, we aimed to identify plasma metabolomic biomarkers of dietary patterns and explored whether these metabolites mediate the relationship between diet and healthy aging, as assessed by the frailty index (FI) in 806 participants of the Baltimore Longitudinal Study of Aging. Adherence to different dietary patterns was evaluated using the Mediterranean diet score (MDS), Mediterranean-DASH Diet Intervention for Neurodegenerative Delay (MIND) score, and Alternate Healthy Eating Index-2010 (AHEI). Associations between diet, FI, and metabolites were assessed using linear regression models. Higher adherence to these dietary patterns was associated with lower FI. We found 236, 218, and 278 metabolites associated with the MDS, MIND, and AHEI, respectively, with 127 common metabolites, which included lipids, tri/di-glycerides, lyso/phosphatidylcholine, amino acids, bile acids, ceramides, cholesterol esters, fatty acids and acylcarnitines, indoles, and sphingomyelins. Metabolomic signatures of diet explained 28%, 37%, and 38% of the variance of the MDS, MIND, and AHEI, respectively. Signatures of MIND and AHEI mediated 55% and 61% of the association between each dietary pattern with FI, while the mediating effect of MDS signature was not statistically significant. The high number of metabolites associated with the different dietary patterns supports the notion of common mechanisms that underly the relationship between diet and frailty. The identification of multiple metabolite classes suggests that the effect of diet is complex and not mediated by any specific biomarkers. Furthermore, these metabolites may serve as biomarkers for poor diet quality to identify individuals for targeted dietary interventions.

Probiotics, Prebiotics, and Synbiotics Improve Uremic, Inflammatory, and Gastrointestinal Symptoms in End-Stage Renal Disease With Dialysis: A Network Meta-Analysis of Randomized Controlled Trials

Background

Probiotics, prebiotics, and synbiotics are three different supplements to treat end stage renal disease (ESRD) patients by targeting gut bacteria. The comprehensive comparison of the effectiveness of different supplements are lacking.

Objectives

The purpose of this network meta-analysis (NMA) is to assess and rank the efficacy of probiotics, prebiotics, and synbiotics on inflammatory factors, uremic toxins, and gastrointestinal symptoms (GI symptoms) in ESRD patients undergoing dialysis.

Methods

Randomized clinical trials were searched from the PubMed, Embase, and Cochrane Register of Controlled Trials databases, from their inception until 4 September 2021. Random-effect model were used to obtain all estimated outcomes in network meta-analysis (NMA). Effect estimates were presented as mean differences (Mean ± SD) with 95% confidence interval (CI). The comprehensive effects of all treatments were ranked by the surface under the cumulative ranking (SUCRA) probabilities.

Results

Twenty-five studies involved 1,106 participants were included. Prebiotics were superior in decreasing Interleukin-6 (IL-6; SMD –0.74, 95% CI [–1.32, –0.16]) and tumor-necrosis factor-α (TNF-α; SMD –0.59, 95% CI [–1.09, –0.08]), synbiotics were more effective in declining C-reactive protein (CRP; SMD –0.69, 95% CI [–1.14, –0.24]) and endotoxin (SMD –0.83, 95% CI [–1.38, –0.27]). Regarding uremic toxins, prebiotics ranked highest in reducing indoxyl sulfate (IS; SMD –0.43, 95% CI [–0.81, –0.05]), blood urea nitrogen (BUN; SMD –0.42, 95% CI [–0.78, –0.06]), and malondialdehyde (MDA; SMD –1.88, 95% CI [–3.02, –0.75]). Probiotics were rated as best in alleviating GI symptoms (SMD: –0.52, 95% CI [–0.93, –0.1]).

Conclusion

Our research indicated prebiotics were more effective in declining IL-6, TNF-α, IS, MDA, and BUN, synbiotics lowering CRP and endotoxin significantly, and probiotics were beneficial for alleviating GI symptoms, which may contribute to better clinical decisions. This study was registered in PROSPERO (Number: CRD42021277056).

Systematic Review Registration

[http://www.crd.york.ac.uk/PROSPERO], identifier [CRD42021277056].

Effect of daily consumption of probiotic yoghurt on albumin to creatinine ratio, eGFR and metabolic parameters in patients with type 2 diabetes with microalbuminuria: study protocol for a randomised controlled clinical trial

INTRODUCTION

To alleviate clinical symptoms of diabetic nephropathy (DN), several dietary and non-dietary strategies have been suggested. Probiotic-enriched foods, through their effects on modulating microflora, might help these patients control the adverse effects. The current study will be done to examine the effects of probiotic yoghurt consumption on albumin to creatinine ratio, estimated glomerular filtration rate (eGFR) and metabolic parameters in patients with type 2 diabetes with nephropathy.

METHODS AND ANALYSIS

Sixty patients with DN will be recruited in this study. After block matching for sex, body mass index and age, patients will be randomly assigned to receive 300 g/day probiotic yoghurt containing 10⁶ CFU/g Lactobacillus acidophilus and Bifidobacterium lactis strains or 300 g/day plain yoghurt daily for 8 weeks. Weight, height and waist circumference will be measured at study baseline and after the intervention. Biochemical indicators including glycaemic measures (haemoglobin A1c (HbA1c), fasting blood sugar (FBS)), inflammatory markers (high sensitivity-C reactive protein), lipid profile (total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL)) and finally renal makers (creatinine, albumin to creatinine ratio, eGFR) will be assessed at study baseline and at the end of the trial.

DISCUSSION

Improving the condition of a person with DN is a serious clinical challenge. The use of probiotic supplements has been considered in these people, but the use of probiotic-enriched foods has received less attention.

TRIAL REGISTRATION NUMBER

Iranian Registry of Clinical Trials (www.irct.ir) (IRCT20201125049491N1).

Probiotic Intake and Inflammation in Patients With Chronic Kidney Disease: An Analysis of the CKD-REIN Cohort

Background and Aims

Little is known about the effects of probiotics on inflammation in the context of chronic kidney disease (CKD). We investigated the association between probiotic intake and inflammation in patients with moderate-to-advanced CKD.

Methods

We performed a cross-sectional study of 888 patients with stage 3–5 CKD and data on serum C-reactive protein (CRP) levels and a concomitant food frequency questionnaire. We estimated the odds ratios (ORs) [95% confidence interval (CI)] for various CRP thresholds (>3, >4, >5, >6, and >7 mg/L) associated with three intake categories (no yoghurt, ordinary yoghurt, and probiotics from yoghurts or dietary supplements) and two frequency categories (daily or less than daily).

Results

The 888 study participants (median age: 70; men: 65%) had a median estimated glomerular filtration rate of 28.6 mL/min/1.73 m² and a median [interquartile range] CRP level of 3.0 [1.6, 7.0] mg/L. Fifty-seven percent consumed ordinary yoghurt and 30% consumed probiotic yoghurt. The median intake frequency for yoghurt and probiotics was 7 per week. Relative to participants not consuming yoghurt, the ORs [95% CI] for CRP > 6 or >7 mg/L were significantly lower for participants consuming ordinary yoghurt (0.58 [0.37, 0.93] and 0.57 [0.35, 0.91], respectively) and for participants consuming probiotics (0.54 [0.33, 0.9] and 0.48 [0.28, 0.81], respectively), independently of age, sex, body mass index, CKD stage, cardiovascular disease, and fibre, protein and total energy intakes. The ORs were not significantly lower for CRP thresholds >3, >4, and >5 mg/L and were not significantly greater in daily consumers than in occasional consumers.

Conclusion

We observed independent associations between the consumption of yoghurt or probiotics and lower levels of inflammation in patients with CKD. There was no evidence of a dose-effect relationship.

Clinical Trial Registration

[https://www.clinicaltrials.gov/ct2/show/NCT03381950], identifier [NCT03381950].

Biotic Supplements in Patients With Chronic Kidney Disease: Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

Gut flora imbalance characterizes patients with chronic kidney disease (CKD). Although biotic supplementation has been proposed to lessen inflammation and oxidative stress and, thus, reduce the risk of progressive kidney damage and cardiovascular disease, the effects remain controversial. We conducted a meta-analysis to assess the therapeutic benefits of biotics in CKD.

METHODS

PubMed, Embase, and Cochrane databases were systematically searched for randomized controlled trials that evaluated any biotic (prebiotic, probiotic, synbiotics) supplements in patients with CKD (CKD, stage 3-4 to end-stage renal disease). Primary endpoints included changes in renal function, markers of inflammation, and oxidative stress. Secondary endpoints included changes in levels of uremic toxins and variations in lipid metabolism.

RESULTS

Twenty-three eligible studies included 842 participants. In a pooled-analysis, biotics did not change estimated glomerular filtration rate (mean difference [MD] = 0.08, P = .92) or serum albumin (MD = -0.01, P = .86), although prebiotics reduced serum creatinine (standardized mean difference [SMD] = -0.23, P = .009) and blood urea nitrogen (MD = -6.05, P < .00001). Biotics improved total antioxidative capacity (SMD = 0.37, P = .007) and malondialdehyde (SMD = -0.96, P = .006) and reduced the inflammatory marker interleukin-6 (SMD = -0.30, P = .01) although not C-reactive protein (SMD = -0.22, P = .20). Biotic intervention reduced some uremic toxins, including p-cresol sulfate (SMD = -2.18, P < .0001) and indoxyl sulfate (MD = -5.14, P = .0009), which decreased in dialysis-dependent patients. Another toxin, indole-3-acetic acid (MD = -0.22, P = .63), did not change. Lipids were unaffected by biotic intervention (total cholesterol: SMD = -0.01, P = .89; high-density lipoprotein: SMD = -0.08, P = .76; low-density lipoprotein: MD = 3.54, P = .28; triglyceride: MD = -2.26, P = .58).

CONCLUSION

The results highlight the favorable influence of biotics on circulating markers of creatinine, oxidant stress (malondialdehyde, total antioxidative capacity), inflammation (interleukin-6), and uremic toxins (p-cresol sulfate) in patients with CKD. Biotics did not affect estimated glomerular filtration rate, albumin, indole-3-acetic acid, or lipids in either predialysis or dialysis patients.

Effects of Probiotics, Prebiotics, and Synbiotics on Uremic Toxins, Inflammation, and Oxidative Stress in Hemodialysis Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

The dysbiosis of gut microbiota may cause many complications in patients with end-stage renal disease, which may be alleviated by probiotic, prebiotic, and synbiotic supplementation. The aim of this systematic review and meta-analysis was to assess the effects of these supplementations on circulatory uremic toxins, biomarkers of inflammation, and oxidative stress in hemodialysis patients. We searched the EMBASE, MEDLINE, Web of Science, and Cochrane Library databases until 8 August 2021. Randomized controlled trials evaluating adult patients receiving hemodialysis were included. The pooled results from 23 studies with 931 hemodialysis patients indicated that interventions significantly decreased the circulating levels of p-cresyl sulfate (standardized mean difference (SMD): 0.38; 95% CI: -0.61, -0.15; p = 0.001), endotoxins (SMD: -0.58; 95% CI: -0.99, -0.18; p = 0.005), malondialdehyde (SMD: -1.16; 95% CI: -1.81, -0.52; p = 0.0004), C-reactive proteins (CRP) (SMD: -0.61; 95% CI: -0.99, -0.23; p = 0.002), and interleukin 6 (SMD: -0.92; 95% CI: -1.51, -0.33; p = 0.002), and improved the total antioxidant capacity (SMD: 0.89; 95% CI: 0.49, 1.30; p < 0.0001) and glutathione (SMD: 0.40; 95% CI: 0.14, 0.66; p = 0.003) when compared to the placebo group. Our results suggest that treatment with probiotics, prebiotics, and synbiotics may help alleviate uremic toxin levels, oxidative stress, and the inflammatory status in hemodialysis patients.

Interplay between gut microbiota, bone health and vascular calcification in chronic kidney disease

Deregulations in gut microbiota may play a role in vascular and bone disease in chronic kidney disease (CKD). As glomerular filtration rate declines, the colon becomes more important as a site of excretion of urea and uric acid, and an increased bacterial proteolytic fermentation alters the gut microbial balance. A diet with limited amounts of fibre, as well as certain medications (eg phosphate binders, iron supplementation, antibiotics) further contribute to changes in gut microbiota composition among CKD patients. At the same time, both vascular calcification and bone disease are common in patients with advanced kidney disease. This narrative review describes emerging evidence on gut dysbiosis, vascular calcification, bone demineralization and their interrelationship termed the 'gut-bone-vascular axis' in progressive CKD. The role of diet, gut microbial metabolites (ie indoxyl sulphate, p-cresyl sulphate, trimethylamine N-oxide (TMAO) and short-chain fatty acids (SCFA)), vitamin K deficiency, inflammatory cytokines and their impact on both bone health and vascular calcification are discussed. This framework may open up novel preventive and therapeutic approaches targeting the microbiome in an attempt to improve cardiovascular and bone health in CKD.

Specific alterations in gut microbiota in patients with chronic kidney disease: an updated systematic review

BACKGROUND

Emerging evidence demonstrates that gut dysbiosis is implicated in the pathogenesis of chronic kidney disease (CKD) with underlying mechanisms involving mucosal and/or systematic immunity or metabolic disorders. However, the profile of gut microbiota in patients with CKD has not been completely explored.

METHODS

Databases from their date of inception to 31 March 2020 were systematically searched for case-control or cross-sectional studies comparing the gut microbial profiles in adult patients with CKD or end-stage renal disease (ESRD) with those in healthy controls. Quantitative analysis of alterations in gut microbial profiles was conducted.

RESULTS

Twenty-five studies with a total of 1436 CKD patients and 918 healthy controls were included. The present study supports the increased abundance of, phylum Proteobacteria and Fusobacteria, genus Escherichia_Shigella, Desulfovibrio, and Streptococcus, while lower abundance of genus Roseburia, Faecalibacterium, Pyramidobacter, Prevotellaceae_UCG-001, and Prevotella_9 in patients with CKD; and increased abundance of phylum Proteobacteria, and genus Streptococcus and Fusobacterium, while lower abundance of Prevotella, Coprococcus, Megamonas, and Faecalibacterium in patients with ESRD. Moreover, higher concentrations of trimethylamine-N-oxide and p-cresyl sulfate and lower concentrations of short-chain fatty acids were observed. Gut permeability in patients with CKD was not determined due to the heterogeneity of selected parameters.

CONCLUSIONS

Specific alterations of gut microbial parameters in patients with CKD were identified. However, a full picture of the gut microbiota could not be drawn from the data due to the differences in methodology, and qualitative and incomplete reporting of different studies.

Tailored synbiotic powder (functional food) to prevent hyperphosphataemia (kidney disorder)

Hyperphosphataemia is treated with phosphate binders, which can cause adverse effects. Spray-dried synbiotic powder (SP) composed of Lactobacillus casei JCM1134 (a phosphate-accumulating organism; PAO) and Aloe vera is potentially a safer alternative for efficient phosphate removal. In this study, a novel strategy was developed; lysine-derivatized deacetylated A. vera (DAVK) was synthesised and fabricated on phosphate-deficient PAO (PDP) for efficient phosphate transfer and then spray-dried with the supernatant of DAV centrifugation to form a sacrificial layer on PDP for SP integrity during gastric passage. In vitro experiments revealed that PAO removed only 1.6% of the phosphate from synthetic media, whereas SP removed 89%, 87%, and 67% (w/v) of the phosphate from milk, soft drink, and synthetic media, respectively, confirming the protective role of A. vera and efficient phosphate transport. Compared with commercial binders, SP effectively removed phosphate from synthetic media, whereas SP and CaCO3 exhibited comparative results for milk and soft drink. Importantly, CaCO3 caused hypercalcaemia. Thus, the described SP presents a promising tool to prevent hyperphosphataemia. This study also revealed a novel factor: diets of patients with chronic kidney disease should be monitored to determine the optimal phosphate binders, as phosphate removal performance depends on the accessible phosphate forms.